When we told the Vender then he just told that we are using solder paste with 62/36/2 combination & the components are lead free so there is prob. of dry soldering. While we are using chip cap from other vendor (which are not lead free )with same profile & solder paste (Kester277) we did not get any prob. Please suggest that is this the only reason or what may be other which we are not condering.

I have also tried by increasing tepmrature by 245*c on board actually but not working.

It sounds like you're exhausing your flux activity on this component proir to reflow.

We'd start with the reflow recipe suggested by your paste supplier. If the component lead doesn't flow well try: * Raising the peak temperature in 5*C increments. * Decreasing the soak period * Decreasing the ramp to peak

Thanx for your only reply!! I already increased temprature now its actualy on board is 240*c. I would like to discuss one more thing if I go for lead free solder paste & using some components wich are not lead free then what will be the result. Has anybody experince on it.

Are the components 100% tin plated? Thats what we are buying and we have no problem at all soldering with the same profiles we always have used and we use the same alloy as you but different mfg. We have not had problems soldering tin plated parts with Amtech, Indium or Alpha paste. You may want to get another vendors parts and try them. Might just be a plating problem.

MKS, You do not need to reach a temp of 245C to form a joint and surely not for 0603s. Since you are using such a high temp your flux is getting dried out.. Also if you are going to reach a peak of 245C on a brd that has Sn/Pb compt and Pb-free.. you are going to cause reliability issues to the Sn/Pb compt (heat sensitive)... You might want to reach a Peak of 225C max..with TAL (183) around 80sec.. that should allow joint formation for both Sn/Pb and Pb-free compt.